The U.S. labor board said Monday that Wal-Mart Stores Inc. may have illegally disciplined workers, including some who were allegedly fired for protesting the retailer’s employee policies.

Walmart “unlawfully threatened, disciplined and/or terminated employees” at stores in 13 states for protesting working conditions, according to a statement from the National Labor Relations Board.

The board will seek a settlement with Walmart that may include rehiring employees with back pay for actions taken against about 117 people, according to Dan Schlademan, director of Making Change at Walmart, a campaign to pressure the company to improve wages and working conditions.

“Walmart will be given a chance to settle this,” Schlademan said on a conference call with reporters. “If Walmart does not agree then, the board will make an official charge in the case.”

David Tovar, a spokesman for Walmart, did not return phone calls seeking comment.

The board rejected complaints that Walmart interfered with some employees’ right to strike at stores in Illinois and Texas or retaliated against employees at stores in California and Washington.

The NLRB case stems from charges filed against the retailer one year ago, when Walmart managers tried to discourage employees from taking part in protests ahead of “Black Friday” after Thanksgiving, one of the busiest shopping days of the year.

The case also covers 100 striking workers who took their complaints to the company’s shareholder meeting in Bentonville, Ark., in June, according to a statement from Our Walmart, an association of Walmart employees.

At least 43 workers were disciplined and another 23 worker-leaders were fired, the statement says.

Both Our Walmart and Making Change at Walmart are supported by the United Food and Commercial Workers International Union.